Bifold doors – everything you’ve ever wanted to know

Our expert guide answers every question you have if you're considering bifold doors
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  • Whether you’re building, extending or simply looking to revamp your home, it’s important to find the right door solution. Bifold doors are one of the most popular – and on trend – ways to open up your home.

    Like skylights, bifold doors flood your home with light, but work doubly hard by providing an access point to the outdoors. Plus, unlike sliding or French doors, bifolding designs stack neatly out of the way. This offers wonderfully unobstructed views of your garden, and creates an expansive feeling inside.

    However, when you’re making such an investment, you’re bound to have a fair few questions. We’ve rounded up the experts to make sure you’ve got all the info you want and need.

    What is a bifold door?

    Open plan kitchen living room with open bifolding doors

    Image credit: Schüco/Tim Crocker

    First things first. What actually is a bifold door? It’s become a ubiquitous term for contemporary wall-to-wall glazing, but it does have its own unique properties.

    ‘Bifold doors are glazed doors with individual panels that fold into narrow stacks and glide to the side either outwards or inwards,’ explains Jordan Vincent, Architectural Project Manager at Schüco. ‘This allows you to open up your home completely to the outdoors.’

    Do bifold doors add value to homes?

    Exterior of white house with bifolding doors with green inner track

    Image credit: Origin

    When you’re adding bifold doors to your home, you want to know if it’s going to add value, or if it’s just a superficial aesthetic addition. Luckily, the many benefits of bifolds mean that they are proven to increase the value of your space.

    ‘Some experts estimate that bifolding doors can add around 5-10% to the valuation of a property,’ advises Victoria Brocklesby, COO, Origin. ‘Generally, installing great glazing will instantly improve kerb appeal and the additional light bi-folds bring into a home can transform the feel of indoor spaces to make them more enticing.’

    ‘Our own research shows that over half of Brits that don’t have enough natural light in their home are looking to move or renovate in the next 12 months, which shows the real-life value of fixtures like bifolds.’

    ‘Installing bifold doors can add value to your home by creating a real wow factor,’ agrees Jordan from Schüco. ‘By filling your home with natural light and increasing the sense of space bifold doors can make your home more appealing to potential buyers – if you can bear to leave. It’s important to choose high quality doors from a reputable brand that will stand the test of time as well as to use a qualified installer.’

    What are the benefits of bifold doors?

    Open plan kitchen diner with bifolding doors and windows

    Image credit: IDSystems

    So why are bifold doors seen as superior to other folding door solutions? ‘The real benefit of bifold doors is their ability to completely open up an aperture,’ says David Clarke, Marketing Manager, IDSystems. ‘When the doors are stacked back to the side of the opening they can create a completely seamless transition between inside and out which is ideal for entertaining and for making the most of warm, sunny days.’

    ‘Bifold doors instantly transform a living space like no other home improvement can,’ adds Victoria from Origin. ‘They open a multitude of possibilities for homeowners by changing the functionality of spaces, increasing natural light, and creating a seamless transition from inside to outside. Due to their ability to offer unique low, non-weathered threshold systems, features from the interior of a home, like tiled or wooden floors, can be continued into the garden to blend the two spaces, to enhance and extend the useable living area.’

    They’re also a great addition for more petite areas. ‘Bifold doors are perfect for smaller openings as they can open up to 90% of the aperture,’ notes Matt Higgs, Director, Kloeber. ‘Opening configuration is key when designing how the bifolds fit in to the space and how they’ll be used. Think about where furniture will be placed and the flow from internal to external. Consider a single opening traffic door, to avoid opening up the whole set (ideal for children or pets that want to access the garden). A level threshold with similar flooring inside and out will help create a cohesive living space, perfect for entertaining.’

    What are the problems with bi-fold doors?

    Patio with bifold doors opening into open plan living area

    Image credit: Future PLC/Colin Poole

    Although that all sounds great – nothing comes without a downside. The main issues with bifolding doors are connected to the size of the frames and movement problems.

    Compared to sliding doors, bi-fold doors have more framing profiles visible when they are closed. ‘Typically, the British climate does not allow the doors to be completely open for more than 3 or 4 weeks a year so it is likely the bifold doors will be closed more often than open,’ notes David from IDSystems. ‘In those circumstances sliding doors, with larger panels and narrower frames maybe the more suitable option – particularly for larger openings where the bigger panes of glass in sliding doors really come into their own.’

    In terms of movement, a lot of the issues can be avoided by investing in the best quality systems you can. ‘Above all, a well-designed bi-folding door set should be easy to operate,’ says Rob Owens, Product Manager, Westbury Windows and Joinery. ‘Heavy, clunky, loud doors that are prone to getting stuck will become unused and neglected, making them a poor investment. If manufactured to precise measurements, they will flawlessly fold and slide with smooth movements.’

    ‘One discrepancy in the door sizes, even by a single millimetre on either side, can affect the functionality of the whole unit and prevent it from opening,’ continues Rob. ‘This is why choosing a quality product that has been crafted by experts is certainly a worthwhile investment.’

    How much do bifold doors cost?

    Double height living room with open bifold doors

    Image credit: IDSystems

    Just as there’s variation in how much an extension costs, bifolds have quite the range. This depends on size, quality and material.

    ‘Bifold doors start from around £900 per panel including installation,’ advises David from IDSystems. ‘But some systems are priced from £1600 per panel.’

    Alternatively, for a more budget option, expect to pay around £2,000 for a three-door set of uPVC bifold doors. Also, installation will be extra – usually around another £6-800.

    How many bifold doors do I need?

    Open plan kitchen living room with bifolding doors

    Image credit: Kloeber

    The dimensions of your opening will determine the number of doors. Odd numbers look best – three or five are the most popular. If everyday access is required, make sure there is a single lead door that can be opened outward.

    ‘There are few limitations to the number of panels, or ‘sashes’, used in a bi-fold door,’ notes Victoria from Origin. ‘The minimum is two, while there is no real maximum. Opting for bespoke doors means you can choose the width and configuration of the panels, depending on how many you would like. However, homeowners should keep in mind that bi-fold doors that span over 6 metres in one aperture tend to require tracks to be connected to one another.’

    That said, less is more in terms of bifold doors. ‘Bifold door panels are typically around 900mm to 1100mm wide,’ advises David from IDSystems. ‘So the easiest way of working out how many panels you require is to divide the opening size by the panel width. If in doubt it is always best to go for the fewest number of panels possible so that you maximise the amount of glass because more panels would mean more visible frame.’

    ‘We wouldn’t recommend going for panels over 1200mm. This is because the weight of the doors can impact the longer term performance of the system. And at that size the panels will extend out on to your patio and take space when opened.’

    What are the best materials for bifold doors?

    Kitchen with island and white wooden bifold doors

    Image credit: Westbury

    ‘Bi-fold doors are made from a variety of materials, including aluminium, uPVC, and composite,’ says Victoria from Origin. ‘High-grade aluminium is the modern choice as it offers great aesthetics. It is also far more durable than uPVC, meaning your doors will maintain their alignment better over their lifetime. Powder coated aluminium is also more resilient to corroding, rotting, or warping.’

    For a more classic look, good quality wood is another option. ‘While bi-fold doors are available in a range of different materials, to achieve an elegant and timeless look then timber doors will look beautiful and are also highly functional when a premium wood, such as Accoya is used,’ advises Rob from Westbury. ‘Using a strong and durable wood like Accoya, which is an engineered timber made only from sustainable tree species, will ensure the longevity of your bi-fold door.’

    Both aluminium and timber have different aspects to take into account, so consider what’s right for you. ‘Timber is very strong, secure, thermally efficient, sustainable and cost effective,’ notes Matt from Kloeber. ‘Meanwhile, aluminium is low maintenance and has slim sightlines.’

    Are bifold doors weatherproof and will they make a room feel cold?

    Corner of house with two sets of bifold doors

    Image credit: Kloeber

    Large glass expanses can feel chilly compared to a solid wall so decent thermal performance is crucial. For how to keep your house warm in winter look for the lowest U-values, which indicates the heat lost in watts per square metre. To comply with building regulations, bifold doors must be 1.8W/(m2k) for replacements, or 2.0W/(m2k) in new builds and extensions. But there’s nothing to stop you aiming lower – triple glazing go down to 1.3W. Ensure they pass the weathertightness test (BS 6375 Part 1).

    Do bifold doors need a track?

    Kitchen extension with skylights and bifold doors

    Image credit: IDSystems

    Easy question – yes they do. Bifolds are mounted on tracks and should slide, fold and stack smoothly and with minimal force.

    Flush fitting tracks with recesses into the floor reduce trip hazards, and look slick. However, be aware that they can make it harder to achieve a watertight fit.

    Are bifold doors safe and secure?

    Dining room with open bifolding doors onto patio

    Image credit: Westbury

    As a large access point into your home, bifolds must conform to current security standards and the lead door must have a multi-point locking system. For extra peace of mind, invest in a lock featuring an anti-pick/drill cylinder. If you have little ones running around, request finger-safe gaskets to prevent doors slamming shut on tiny hands.

    ‘Bi-folding doors are very secure, as they have multiple locks spread across the leaves,’ adds Rob from Westbury.

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